Assessing the stratospheric temperature response to volcanic sulfate injections: insights from a multi-model framework

Volcanic sulfate injections into the stratosphere following major eruptions are able to modulate climate, as demonstrated by the well-documented 1991 Mt. Pinatubo eruption. Understanding the climate response to such events is critical, especially in the context of potential solar radiation management strategies to counteract climate change. An important part of volcanic impact on the atmospheric system originates from volcano-induced lower stratospheric heating that leads to changes in stratospheric circulation and transport and possibly in stratosphere-troposphere coupling and regional tropospheric circulation. Previous modeling studies have shown diverse results concerning these effects, partly due to model uncertainties and differences in simulation setup or study design, such as prescribed aerosols and/or chemistry, while the feedbacks between these system components were shown to be significant.

This study evaluates the tropical stratospheric temperature response to the Mt. Pinatubo eruption using eight global models with interactive aerosol microphysics. All models adhered to the Historical Eruptions SO2 Emission Assessment (HErSEA) protocol under the Interactive Stratospheric Aerosol Model Intercomparison Project (ISA-MIP). We focus on the uncertainties related to initial SO2 emission amounts and injection heights. Results reveal that while models exhibit consistent sensitivity to initial SO2 amounts and injection heights, the magnitude and extent of the stratospheric temperature response vary. By comparing model outputs and observations, this study enhances our understanding of individual model performances and the current multi-model uncertainty range and provides critical insights for future climate impact assessments of volcanic eruptions.